The interactions between environment and drug actions will be explored and the role of the central and peripheral sympathetic nervous systems in these interactions will be examined. Major emphasis will be placed on the functional role of endogenous catecholamines. An examination will be made of the properties of those drugs which, by disrupting catecholamine synthesis or by replacing tissue stores of catecholamines (possible 'false transmitters'), may provide investigators with tools with which they can examine the functional role of cathecholamines in various pharmacological, physiological, behavioral, and endocrinological processes.